Compact pump/air separator apparatus

ABSTRACT

A pump/air separator apparatus for use in dispensing gasoline includes an air separator of the cyclone type in which air and a low percentage of gasoline are removed from the pressurized gasoline by the air separator, with the air being vented to the atmosphere and the gasoline being returned to the suction side of the pump. Simultaneously pure gasoline is delivered from the air separator through an outlet valve to a meter and then to the nozzle dispenser, and any excess of such pure gasoline is bypassed back to the suction side of the pump.

Zanoni 1 Feb. 13, 1973 1 COMPACT PUMP/AIR SEPARATOR 2,163,951 6/1939 LaBour ..55/2o3 x APPARATUS [75] Inventor: Paul Zanoni, Muskegon,Mich. 522222 %ffigz t $i iifg [73] Assignee: Bennett Pump Inc., Muskegon,Attorney-Thomas Marsha" Mich.

[57] ABSTRACT [22] F1led: March 26, 1971 A pump/air separator apparatusfor use in dispensing [21] Appl' 128,291 gasoline includes an airseparator of the cyclone type in which air and a low percentage ofgasoline are 52 us. c1 .55/204 removed from the Pressurized gaSOhhe bythe ah 51 Int. Cl. ..B0ld 19/00 Separamr, with the air being vented tothe atmosphere [58] Field of Search 55/41, 165, 169, 199, 2O1 206; andthe gasoline being returned to the suction side of 73/200, 228; 222/72333 the pump. Simultaneously pure gasoline is delivered from the airseparator through an outlet valve to a [56] References Cited meter andthen to the nozzle dispenser, and any excess of such pure gasoline isby-passed back to the suction UNITED STATES PATENTS side of the pump.

2,275,355 3/1942 Finken ..55/2Q4 X 9 Claims, 7 Drawing Figures 2,351,3316/1944 Goldberg. ..222/72 2,005,466 6/1935 La Bour ..55/l04 XPATENTEDFEB13I975 3.715.863

SHEET 2 OF 3 B YPASS ML VE INVENTOR F Q 2 Baa/L ZANONI BYfi MMPAIENTEDFEBHI ms 3.715863 saw a or a INVENTOR.

fLm PQl/L Zwaw FIG- 3 BY ATI'OQIVEV COMPACT PUMP/AIR SEPARATOR APPARATUSBACKGROUND OF THE INVENTION The present invention relates to a gasolinedispensing pump provided with an air separator, the latter being capableof separating air and vapor from the gasoline received from the storagetank.

A specific application of the present device is in a gasoline dispensinginstallation where a pump located above ground level delivers gasolinefrom an underground storage tank through a gasoline meter connected to acomputer and register, and thence through a flexible hose and adispensing nozzle at the delivery end of that hose, where the gasolineflow is controlled by operation of a valve in the nozzle. Because thegasoline must be lifted from the underground storage tank, the suctionside of the pump is necessarily below atmospheric pressure. Thus, if anyleaks exist in the piping between the storage tank and the pumpingapparatus, air would be introduced into the system. Since the meter usedis a positive displacement type which will measure both air and liquid,in order to satisfy the various governmental regulations governingcommercial gasoline dispensing equipment, it is necessary to separatethe air before measuring the volume of delivery.

In the usual gasoline dispensing installation, the pumping apparatus andthe separator apparatus are separate and distinct units interconnectedby a suitable conduit. The separator allows the bubbles in thepressurized gasoline leaving the pump to rise in a liquid surface underthe action of gravity, where the air is separated from the liquid. Thisis not entirely satisfactory since small bubbles take a very long timeto rise, and furthermore, an air separator of this type requires a verylarge chamber. The latter requirement gives rise to a critical problemin light of the limited space available in the dispensing stand orpedestal for housing the necessary equipment for pumping and dispensinggasoline. Many other factors must also be taken into consideration in agasoline dispensing installation, one factor being the rigid requirementfor accuracy of metering and delivering of gasoline as set forth invarious government regulations. Another factor to be considered in agasoline dispensing installation is the problem caused by the wide andinfinite variation in rates of delivery flow of gasoline, and thefrequent and abrupt changes in flow rates. This irregularity in flowrates is caused by operation of the control valve at the deliverynozzle, and gives rise to a problem of effectively eliminating the airfrom the pressurized gasoline leaving the pump in view of the effects ofpressure on the solubility of air in gasoline.

As mentioned above, one prior art approach (as shown in U.S. Pat. No.2,351,331) to achieving the separation of air from gasoline receivedfrom a storage tank is to provide a rather large air separator (element3 of said U.S. Pat. No. 2,351,331) disposed downstream of and completelyseparate from the main gasoline pump. Other systems have employedarrangements of check valves which are operated in response to a signaldeveloped during operation of the pump. The check valve arrangementtakes a signal from the operation of the pump which detects changes inthe airto-liquid ratio of the fluid being forced into the flow lines,and the signal produced by such device operates various valve means toprevent the metering of all but a small quantity of fluid unless thesignal indicates a normal fluid flow condition. This type of airseparation system is extremely complex, thereby resulting in high costand questionable reliability.

SUMMARY OF THE INVENTION The pump/air separator of the subject inventioncomprises a housing having at least three cavities. A pump is mounted inone cavity and its suction side is connected to the underground gasstorage tank. Pressurized gasoline from the pump is directed to an airseparator where a scavenged flow of gasoline and air bubbles is thenpassed through the third cavity, while pure gasoline is passed to thesecond cavity. The pure gasoline is either delivered to the meteringdevice for subsequent delivery to the flexible hose and dispensingnozzle, or by-passed back to the suction side of the pump. The scavengedflow collects in the third cavity, with the air separating from thegasoline and being discharged through a vent in the housing. Thegasoline in the third cavity is controllably returned to the suctionside of the pump.

Accordingly, it is a primary object of this invention to provide acompact apparatus embodying means for pumping pressurized gasoline andmeans for separating air and vapor from the pressurized gasoline priorto dispensing. Thus, the compact apparatus of the subject inventionsatisfies the critical space requirements for gasoline dispensingapparatus. It is a further object of this invention to provide animproved air separation mechanism which will eliminate substantially allof the air in the pressurized gasoline regardless of the varyingconditions under which the associated pump operates. It is a furtherobject of the invention to provide compact pump/air separator which willsatisfy all applicable governmental requirements, including the completeelimination of all air that can possibly be eliminated regardless ofinstallation conditions and regardless of the particular conditionsunder which the operator operates the installation, and especially toaccomplish these objects in a manner which will satisfy the rigidrequirements for accuracy of metering and delivering of gasoline.

The device of this invention accomplishes these results by using acyclone type of device in a manner which is the inverse of the normaluse of such a device. Thus in Marks Handbook (6th Ed.) at page 759reference is made to inertia separators of the cyclone type used in thefield of industrial dust collectors. In such applications such a deviceseparates heavier particles of dust, etc., from the lighter gases byinertia separation. In the device of this invention the lighter fluidcomponents of a fluid stream are separated from the heavier. Thus air orvapor entrained in gasoline is separated before the gasoline isdelivered to the metering device and hence to the outlet nozzle.Similarly the device of this invention may be used to separateparticulate matter of a lighter density than the desired fluid or toseparate the lighter of two different density and immiscible liquids,i.e., to separate oil from water. While the description below is relatedonly to the specific preferred embodiment of a gasoline pump/airseparator, it should be understood that any device which embodies themeans described to accomplish the functions performed is within thescope of this inven tion.

Further objects and advantages of the invention wilt appear from thefollowing description, taken in conjunction with the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically illustrates thecompact pump/air separator of the subject invention;

FIG. 2 illustrates a partial cross-sectional view of a compact pump/airseparator of the subject invention;

FIG. 3 illustrates a partial sectional view taken along line 3-3 of FIG.2;

FIG. 4 illustrates a sectional view taken through the inlet and filterassembly of the subject compact pump/air separator;

FIG. 5 illustrates a partial sectional view taken along line 55 of FIG.2;

FIG. 6 illustrates a sectional view taken along the control valve of thesubject compact pump/air separator; and

FIG. 7 illustrates a sectional view taken along the bypass valve of thesubject compact pump/air separator.

DESCRIPTION OF THE PREFERRED EMBODIMENT A schematic illustration of thecompact pump/air separator of the subject invention is shown in FIG. i.The compact pump/air separator is designated by the numeral 1 and isconnected to an underground gasoline storage tank 2 via suction piping3. The compact pump/air separator 1 comprises a pump 4 of the constantdelivery type which is directly connected to the suction piping 3 at itsinlet suction end, and is connected at its outlet or pressure end to anair separator 5. All of the flow from the constant delivery pump isdirected through the air separator 5 and the air separator 5 functionsto separate pure gasoline (i.e., without air and vapor) from a scavengedflow consisting of a small percentage of the liquid gasoline flowingfrom the pump 4 and the air and vapor in the flow. The pure gasoline isconducted from the air separator and is passed either through a controlvalve 6 and out of the compact pump/air separator to the delivery hosefor dispensing or, alternatively, through a by-pass valve 7 and back tothe inlet or suction side of the pump 4. The scavenged flow from the airseparator is conducted to a cavity or atmospheric chamber 8 in thecompact pump/air separator unit. Cavity 8 is provided with conditionsconducive to static air-separation effects, i.e., the tendency of air torise and separate from liquid by gravity. The air is permitted to ventto the atmosphere, while the remainder of the scavenged flow consistingof pure gasoline is collected in the cavity and is conducted through asuitable orifice controlled by a valve 9, preferably of the float valvetype, and back to the inlet or suction side of the constant deliverypump 4.

The arrangement of elements in the subject pump/air separator providesthe desired compactness for use in gasoline dispensing apparatus and, inaddition, provides an arrangement whereby the by-pass is locateddownstream of the air separator. I-Ieretofore, it has been the commonpractice to mount the by-pass valve in the single conduit extendingbetween the pump and air separator. In that the pressure inthe linesbetween the gasoline storage tank and the pump is below atmosphericpressure, opening of the by-pass line often caused the accumulation ofair in the system causing the pump to become airbound. Hence, with thedispenser nozzle fully closed and all of the flow being recycled throughthe by-pass valve, the air introduced into the by-pass line wouldaccumulate in the by-pass line and pump, thereby affecting theefficiency of the pump. With the compact pump/air separator of thesubject invention, as illustrated in FIG. 1, this condition is obviatedby placing the by-pass valve downstream of the separator whereby onlypure gasoline is passed through the by-pass line. Other advantages ofthis system will become apparent as the preferred embodiment of thesubject compact pump/air separator is described with reference to FIGS.2 thru 7.

Turning to FIGS. 2 and 3, a compact pump/air separator of the subjectinvention comprises a housing 20 including three internal cavities A, B,and C which are interconnected, as more fully described below. Housing20 also includes an inlet, designated by numeral 21 and two outlets: (1)an air venting outlet 22 in communication with cavity C; and (2) acontrolled outlet 23 disposed in cavity B.

Referring to FIG. 4, the inlet 21 of the housing 20 is in communicationwith cavity A that includes an enlarged entrance section A to accomodatea filter F. Filter F is located immediately inside the housing andfunctions to prevent the ingestion of foreign particles into the compactpump/air separator. The piping 3 which is in communication with theinlet 21 extends to the underground gasoline storage tank (see FIG. 1).

Cavity A is generally U-shaped in cross-section with a constant deliverypump 30, preferably of the vane type, being located in one leg portionof cavity A. Pump 30 is driven in conventional manner through a shaft 31which is suitably mounted in housing 20, and is connected to drive wheel32 (see FIG. 3) located externally of the housing. The motor (not shown)for driving wheel 32 is located in the gasoline pedestal (notshown), asis the compact pump/air separator of the subject invention.

The other leg of the U shaped cavity A is generally annular incross-section and forms a portion of an air separator, designated bynumeral 40. Located along the longitudinal axis of the separator is atubular scavenging tube 41 which is cantilevered from an internal wall42 of the housing. A restricted orifice 43 is provided through wall 42along the centerline of the scavenging tube 41 thereby interconnectingcavity A to cavity C.

The air separator 40, and hence cavity A, is also in communication withcavity 8 at a location downstream of the entrance 41a to the scavengingtube. As shown in FIGS. 2 and 5, the transitional opening betweencavities A and B is preferably equal to the cross-section of saidcavities whereby no restriction of the flow from cavity A to cavity B iseffected. FIG. 5 also illustrates the position of the scavenging tuberelative to transition region between cavities A and B. As illustrated,the cross-section of the internal walls of the housing 20 defining theair separator 40 is generally annular so as to promote centrifugal orhelical flow of the pressurized gasoline leaving the pump 30, as morefully described hereinafter.

valve 52 is biased in the closed position by spring 54.

The body of valve 52 includes a contoured diffusor 55 which connects totubing 56. The latter extends to the metering device of the gasolinedispensing apparatus (not shown). As illustrated in FIG. 6, thecontrolledoutlet 23 is in the fully opened position whereby puregasoline passes from the cavity B to the metering device and thencethrough a flexible hose and a dispensing nozzle at the delivery end ofthe hose. It is noted that the spring 54 forces the valve 52 to theclosed position when the pump is inoperative, thereby preventing theback-flow of gasoline from the dispensing hose to the cavity B.

A second outlet from the cavity B comprises a bypass outlet 24 thatextends through an internal wall 44 of the housing interconnectingcavity B with cavity A in the region of the suction side of pump 20. Adetailed sectional view of the by-pass valve arrangement is illustratedin FIG. 7, and comprises a slidably mounted seat valve 60 which isbiased toward its closed position by spring 61.

Referring to FIG. 3, cavity C includes a second outlet in a form of atapered orifice 70 consisting of two tapers 70a and 70b interconnectingcavity C to cavity A, in the region of the suction side of pump 30.Orifice 70 is disposed at the lowermost portion of cavity C andspecifically in the region where the pure gasoline of the scavenged flowcollects. Disposed in the cavity C is a float 71 having at its lower enda spherical seat valve 72 and a throttle pin 73, both of which cooperatewith said orifice 70 to perform separate functions during the operatingcycle of the pump as will be described later in detail. The float valve71 is confined to translationable movement by: (l) cooperation of thevalve stem 74 with an internal annular wall 45 of the housing 20; and(2) a guide mechanism 75 which is suitably connected to the upper end ofthe float valve.

The general operation of the compact pump/air separator will now bedescribed. Upon the service station operator removing the nozzledispenser from the pedestal and actuating the pump switch, pump 30 willbegin to rotate thereby creating a suction force for lifting gasolinefrom the storage tank 2 and through piping 3. Gasoline, which includesair and vapor, enters the compact pump/air separator through inlet 21,passing through the filter F and into cavity A adjacent the suction sideof pump 30. The pressure at this point is usually 10-12 inches ofmercury below atmospheric because the gasoline must be lifted from anunderground storage tank. The gasoline then enters the vane pump 30 andis discharged under pressure into the air separator 40. As the gasolineenters the air separator portion of cavity A, the internal constructionof cavity A causes the gasoline to assume a helical flow path orswirling motion. The gasoline enters the air separator with a velocitywhich can be regarded as consisting of two components, namely, V,, whichis the axial component, and V, which is the tangential component.

The average axial velocity and the actual velocity can be calculated bythe following equations:

V Q/A V,, Q/A where Q is the flow in cubic feet per second;

A is the cross-sectional area of the inlet nozzle 76;

A is the cross-sectional area of the separate 40; and

the tangential velocity is express by the relationship V,== V V V3 Thehelix angle is the angle between the tangential velocity and actualvelocity of the gasoline. The helix angle 0 at the entrance to theseparator can be determined by the following relationship:

0= sin "(Va/V) It has been determined that the air separate operates atmaximum efficiency through only a narrow range of helix angles. If thehelix angle is too small, considerable power is consumed in acceleratingthe gasoline, whereas if the helix angle is too large, separation of theair and vapor from the gasoline is not completely effected. It is alsonoted that the input to the air separator may be either tangential oraxial, as long as the proper swirl or helical path is induced to thegasoline flow. As mentioned above, the helix angle is a very importantparameter for the efficient operation of the air separator, and it hasbeen found that the subject separator operates satisfactorily with ahelix angle in the range of 10 to 30. It has also been found that theseparator operates best with an axial velocity (Va) of 3 to 6 ft./sec.The prior art considered it essential that the axial velocity be held aslow as possible in order to promote gravity separation. The actualvelocities were probably no greater than 0.3 to 0.6 ft./sec., thusresulting in a separator chamber which is 10 times greater incross-sectional area than the device of the present invention.

Returning to the operation of the subject pump/air separator, airbubbles and vapor in the gasoline flow will be forced into the center ofthe air separator by the action of centrifugal force caused by theswirling gasoline, and will form a central core in the flow. This coreis collected in the scavenging tube 41 and allowed to exit the airseparator through the orifice 43 and into the cavity C, along a smallpercentage of gasoline. It has been found that 3 to 8 percent of thetotal pressurized gasoline leaving the pump 30 is sufficient to separatesubstantially all of the air bubbles and vapor from the main gasolineflow when the bubbles constitute less than 12 percent of the main flowby volume. Increasing the size of orifice 43 to permit 8 percent of thepressurized gasoline flow to leave the separator through the scavengingtube 41 effectively expands the separating range to 18 percent airbubbles and vapor from the main gasoline flow.

The air and scavenging gasoline flow enter the atmospheric cavity Cwhere the air is vented to the atmosphere through air outlet 22. Whensufficient pure gasoline collects in the cavity C, the float valve 71 isactuated whereby the gasoline collected in the lowermost portion ofcavity C is returned to cavity A in the region of the suction side ofthe pump through the orifice 73.

The main flow of gasoline, now devoid of air bubbles and vapor continuespast the scavenging tube 41 and flows from cavity A to cavity B. Puregasoline leaves cavity B either through the control valve 23 if deliveryis occuring, or through the by-pass valve 24 into cavity A if the pumpflow exceeds the delivery out of the meter and dispensing nozzle.

The arrangement of the subject pump/air separator permits the full pumpflow which is relatively constant to pass through the air separator,while maintaining the swirl conditions which produce the efficientseparation of air and vapor from the pressurized gasoline. At the sametime, the arrangement of elements of the subject pump/air separatorprevents an accumulation of air on the suction side of the pump during acondition of full by-passing of gasoline from the cavity B to the cavityA.

It is noted that the control valve 23 is designed so that in the eventsuction is taken on an empty gasoline storage tank whereby the pumpdischarges only air, sufficient back pressure is provided by the spring54 (see FIG. 6) to force all the air through the scavenging orifice 43.Accordingly, this arrangement maintains only pure liquid gasoline in themeter, flexible hose, and dispensing nozzle, and insures accurateproduct measurement by the metering device of the gasoline dispensingapparatus.

Orifice 43 achieves a second function in addition to its function inconjunction with the air separator scavenging tube 41. The secondfunction is to discharge all the air delivered by the pump in the eventthe storage tank 2 becomes empty while a delivery is being made throughthe dispensing nozzle of the gasoline pump unit. Assuming that thecompact pump/air separator is capable of accommodating 8 percent ofgallons per minute of fluid gasoline flow, or in other words, 1 gallonper minute of gasoline will pass through the scavenging orifice with a15 p.s.i. pressure difference. In the empty storage tank condition, 15gallons per minute of air would be required to pass through the sameorifice. In order to calculate the pressure differential necessary toaccomplish this situation, it is noted that the flow through an orificeis proportional to the square root of the pressure difference. Thisrelationship may be expressed as follows: (1

Q C V Al \where C is a constant of proportionality.

Since air passes through an orifice times more readily than liquidgasoline, it is recognized that 25 gallons per minute of air will passthrough the orifice 43 with a 15 p.s.i. pressure differential. Settingthese values into equation (1) and solving for the constant C results ina determination that the pressure differential is 5.4 p.s.i..Accordingly, using the parameter of a 5.4

p.s.i. pressure differential, it is a relatively simple matter to designthe control valve 23 to maintain this designated differential or backpressure on the scavenging orifice 43. Hence, a flow of 8 percentthrough the scavenging orifice not only provides for efficient airseparator operation, but also provides the capability of meeting theempty tank condition," which is required in retail gas dispensers, in avery simple manner.

The control valve 23 functions to maintain liquid gasoline in the meterand the delivery hose when the pump is not in operation, and to providea back pressure in the cavity C in the event the gasoline storage tankis emptied during a delivery of gasoline; it being noted that either ofthese conditions would force air through the meter which would berecorded as product delivery. During a normal delivery operation, thecontrol valve has no function other than to allow the flow of gasolinefrom the cavity B to the metering device. It should therefore bedesigned to provide a minimum pressure drop when gasoline is beingdelivered to the meter. This is accomplished by providing an unloadingdisc 53a which is closely fitted to the valve body except in the area ofthe opening to the diffusor 55 (see FIG. 6). In this position, the forceof spring 54 is balanced by forces acting on the control valve 23 whicharise from two sources. The first is the momentum of the fluid enteringthe valve 23 through aperture 50. In accordance with the principles ofmomentum, a force is required whenever a fluid stream changes direction.The components are so arranged that this force is supplied by the valve52 and tends to aid in compressing spring 54. The second force is thepressure differential across the unloading disc 53a. The aperture 550 ofdiffusor 55 is the smallest area the fluid stream will encounter in thevalve 23, consequently it will be the highest velocity and lowestpressure. The rear side of the disc 53a is vented to this low pressurearea at the aperture 55a. The area which this pressure difference actsupon is the entire area of the unloading disc 53a which is approximatelyeight times greater than the area of the seat 53. Since the spring 54must be designed to provide at least a 5.4 p.s.i. differential, pressureacross the seat in the closed position, in theory, one eighth of thisdifferential pressure acting on the greater area of the disc 53a, i.e.,0.6 p.s.i. would be sufficient to compress the spring 54 to the openposition. In practice it has been found that due to losses approximatelyone fourth of the pressure drop required to open the valve, i.e., 1.2p.s.i. is required to maintain valve 23 in the open position.

The control valve 23 also provides for a reverse flow relief valve tolimit the pressure of the liquid gasoline maintained in the meter andhose by the control valve 23. The volume of gasoline trapped between thecontrol valve and the nozzle at the end of the hoze when heated willincrease and cause an increase of pressure of the gasoline between thecontrol valve 23 and hoze nozzle valve. To keep the liquid pressurewithin safe limits, a relief valve is provided to maintain the pressureat some reasonable value slightly above the maximum pump pressure. Theliquid is relieved through the air separator 5 of FIG. 1 to theatmospheric chamber 8. This added liquid is returned to the pump throughfloat valve 9 on the next delivery cycle.

The float valve (element 9 of FIG. 1 and element 71 of FIG. 3) must alsoperform two functions. At startup of the compact pump/air separator, thepump must operate to draw gasoline from the storage tank which mayrequire a lift of approximately 20 feet. Even a small leak in thecompact pump/air separator will admit air to the suction side of thepump and destroy the suction vacuum which is required to lift thegasoline from the storage tank. The spherical seat of valve 72 providesfor complete sealing of the float valve 71 when no gasoline is presentin cavity C.

The second requirement of the float valve 71 is to regulate the gasolinelevel in cavity C by providing a throttling action which is controlledby the position of the float. The operation of the float valve is asfollows: At startup, the float valve will be in a closed positionwhether or not gasoline is present in cavity C. As gasoline enters theatmospheric chamber C through the scavenging orifice, the gasoline levelwill rise until the buoyancy forces of the float are sufficient toovercome the weight and the pressure forces acting on the spherical seat72 of float valve 71. At this point the float valve will rise and thepressure forces will act only on the end of the pin 73 which is a muchsmaller area than the spherical seat. This will cause the float to riseto the limit of its motion. The movement of the float valve isrestrained so that the pin 73 will be positioned near the top of thetapered orifice 70b and a considerable area will be available for flowfrom the atmospheric cavity C causing the gasoline level to fall.However, the pressure forces will continue to act on the end of the pin73. To achieve this it is important that the pin 73 be positioned at orslightly below the top of tapered orifice 70b and that the annular arearemaining between the pin and the taper be slightly less than the areaacross the smaller end of the tapered orifice 70b. When the buoyancyforces are equal to the weight and pressure forces, the pin 73 will movedownward with the gasoline level. As the pin 73 moves downward, the areaexposed to the pressure forces remains constant, therefore no new forcesare introduced. The area available for flow from the atmospheric cavityC decreases as the pin 73 moves downward into taper 70b which decreasesthe flow from the cavity C. When the flow entering and leaving thecavity C are the same, the liquid level will remain constant.

In summary, the compact pump/air separator of the subject inventionprovides the desirable characteristics of compactness, efficiency inremoving air and vapor from gasoline, and an arrangement of elementswhich prevents the recycling of air and vapor to the suction side of thepumping unit. Also where a centrifugal pump is employed the device canfunction to separate lighter density particulate matter from a heavierdensity fluid or to separate the lighter density fluid from a heavierdensity fluid which is immiscible with the lighter density fluid.

Although a specific embodiment of the subject pump/air separator hasbeen described hereinabove and illustrated in the drawings it will beunderstood that other constructions of the subject pump/air separatorreadily apparent to those skilled in the art are contemplated to bewithin the scope of this invention.

What is claimed is:

1. A compact pump/air separator comprising:

a housing means having interior wall defining first, second and thirdinternal cavities; said cavities being interconnected; said housingmeans further having inlet means in communication with said firstcavity:

pump means located in said first cavity;

air separator means located in said first cavity and in communicationwith the outlet of the pump means, said air separator being of thetangential entry cyclone type including a scavenging tube located at thecore of the separator wherein air and a small percentage of gasoline arecollected, said scavenging tube being fixed to the wall separating thefirst and third cavities, said wall including an orifice communicatingthe interior of the tube to the third cavity; said air separator beingoperative to convey air and a small percentage of gasoline to said thirdcavity, with the remainder of e gasoline flowing from said air separatormeans to said second cavity; said third cavity including outlet means todischarge the collected air from the housing means and to returngasoline to the suction side of the pump; and

said second cavity including a controlled outlet for discharginggasoline and a by-pass outlet in communication with said first cavityfor recycling gasoline to said pump means when the controlled outlet isrestricted.

2. A compact pump/air separator as in claim 1, wherein said pump meanscomprises a rotary vane pump.

3. A compact pump/air separator as in claim 1, wherein the openingbetween the first and third cavities is tapered and wherein a pin,positioned by a float valve is provided in said third cavity forcontrollably throttling the flow of gasoline from said third cavity tosaid first cavity.

4. Apparatus as in claim 1 wherein the pressurized fluid flowing throughthe air separator of the tangential entry cyclone type assumes a helixangle between and 30.

5. A compact pump/air separator for pressurizing gasoline flow andseparating air and vapor therefrom comprising:

pump means in communication with a source of gasoline;

an air separator of the tangential entry cyclone type in communicationwith the outlet of said pump means and operative to separate a smallpercentage of gasoline and air and vapor from pure gasoline;

valve means located downstream of said air separator to either dischargethe pure gasoline from the compact pump/air separator for dispensing orto return the pure gasoline to the inlet side of said pump means; and

means for separating the air and vapor from the small percentage ofgasoline, said means including a vent to discharge the air and vapor tothe atmosphere and second valve means for returning the gasoline to theinlet side of said pump means.

6. A compact pump/air separator as in claim 5 wherein said pump meanscomprises a rotary vane pump.

7. A compact pump/air separator as in claim 5, wherein said airseparator includes a scavenging tube located at the core of theseparator wherein the air and vapor and small percentage of gasoline arecollected, said scavenging tube being in communication with the meansfor separating the air and vapor from the small percentage of gasoline.

8. A compact pump/air separator as in claim 5 wherein said second valvemeans includes a float valve provided in said means for separating theair and vapor from the small percentage of gasoline to control the flowof gasoline to the inlet side of said pump means.

9. A compact pump/air separator as in claim 5 wherein the pressurizedfluid flowing through the air separator of the tangential entry cyclonetype assumes a helix angle between 10 and 30.

1. A compact pump/air separator comprising: a housing means havinginterior wall defining first, second and third internal cavities; saidcavities being interconnected; said housing means further having inletmeans in communication with said first cavity: pump means located insaid first cavity; air separator means located in said first cavity andin communication with the outlet of the pump means, said air separatorbeing of the tangential entry cyclone type including a scavenging tubelocated at the core of the separator wherein air and a small percentageof gasoline are collected, said scavenging tube being fixed to the wallseparating the first and third cavities, said wall including an orificecommunicating the interior of the tube to the third cavity; said airseparator being operative to convey air and a small percentage ofgasoline to said third cavity, with the remainder of the gasolineflowing from said air separator means to said second cavity; said thirdcavity including outlet means to discharge the collected air from thehousing means and to return gasoline to the suction side of the pump;and said second cavity including a controlled outlet for discharginggasoline and a by-pass outlet in communication with said first cavityfor recycling gasoline to said pump means when the controlled outlet isrestricted.
 1. A compact pump/air separator comprising: a housing meanshaving interior wall defining first, second and third internal cavities;said cavities being interconnected; said housing means further havinginlet means in communication with said first cavity: pump means locatedin said first cavity; air separator means located in said first cavityand in communication with the outlet of the pump means, said airseparator being of the tangential entry cyclone type including ascavenging tube located at the core of the separator wherein air and asmall percentage of gasoline are collected, said scavenging tube beingfixed to the wall separating the first and third cavities, said wallincluding an orifice communicating the interior of the tube to the thirdcavity; said air separator being operative to convey air and a smallpercentage of gasoline to said third cavity, with the remainder of thegasoline flowing from said air separator means to said second cavity;said third cavity including outlet means to discharge the collected airfrom the housing means and to return gasoline to the suction side of thepump; and said second cavity including a controlled outlet fordischarging gasoline and a by-pass outlet in communication with saidfirst cavity for recycling gasoline to said pump means when thecontrolled outlet is restricted.
 2. A compact pump/air separator as inclaim 1, wherein said pump means comprises a rotary vane pump.
 3. Acompact pump/air separator as in claim 1, wherein the opening betweenthe first and third cavities is tapered and wherein a pin, positioned bya float valve is provided in said third cavity for controllablythrottling the flow of gasoline from said third cavity to said firstcavity.
 4. Apparatus as in claim 1 wherein the pressurized fluid flowingthrough the air separator of the tangential entry cyclone type assumes ahelix angle between 10* and 30* .
 5. A compact pump/air separator forpressurizing gasoline flow and separating air and vapor therefromcomprising: pump means in communication with a source of gasoline; anair separator of the tangential entry cyclone type in communication withthe outlet of said pump means and operative to separate a smallpercentage of gasoline and air and vapor from pure gasoline; valve meanslocated downstream of said air separator to either discharge the puregasoline from the compact pump/air separator for dispensing or to returnthe pure gasoline to the inlet side of said pump means; and means forseparating the air and vapor from the small percentage of gasoline, saidmeans including a vent to discharge the air and vapor to the atmosphereand second valve means for returning the gasoline to the inlet side ofsaid pump means.
 6. A compact pump/air separator as in claim 5 whereinsaid pump means comprises a rotary vane pump.
 7. A compact pump/airseparator as in claim 5, wherein said air separator includes ascavenging tube located at the core of the separator wherein the air andvapor and small percentage of gasoline are collected, said scavengingtube being in communication with the means for separating the air andvapor from the small percentage of gasoline.
 8. A compact pump/airseparator as in claim 5 wherein said second valve means includes a floatvalve provided in said means for separating the air and vapor from thesmall percentage of gasoline to control the flow of gasoline to theinlet side of said pump means.